Refactor addCallback to check function type before adding

Simplifies the addCallback method by only adding the callback if the provided function is of type TFunction, aligning with PsychLua's expectations and removing unnecessary null checks.

Co-Authored-By: Homura <[email protected]>

Author: moxie-coder

source/psychlua/Convert.hx

@@ -15,11 +15,9 @@ class Convert
 {
 	public static function addCallback(l:State, name:String, func:Dynamic)
 	{
-		// PsychLua expects the function to be null for local callbacks, too lazy to do something about that
-		if (Type.typeof(func) != TFunction || func == null)
-			return;
-
-		callbacks.set(name, func);
+	    // PsychLua expects the function to be null for local callbacks so if func is not TFunction we don't add the callback here
+	    if (Type.typeof(func) == TFunction)
+			callbacks.set(name, func);
 
         Lua.pushstring(l, name);
         Lua.pushcclosure(l, cpp.Callable.fromStaticFunction(handleCallback), 1);